Adjustable clamp



Nov. 24, 1936. F E, STAHL 2,061,718'

ADJUST-ABLE CLAMP Filed Dec. 241, 1934 2 Sheets-Sheet l Nov. 24, 193s. f F. E. STAHL. 2,061,718

ADJUSTABLE CLAMP Filed Deo. 21, 1934 2 sheets-sheet 2 Zw/venida FRANK E. STAHL other uses to which it may be put.

Patented Nouv. 24, '1936 UNITI-:D sTATEs PATENT OFFICE Columbus McKinn on Chain Corporation,

Tonawanda, N. Y., a corporation of New York Application December 21,1934, sei-mno. '158,671

`2 claims. (ci. 9o-59) My invention relates in generalto l:adjustable clamps, and in particular to a clampused upon jigs or work piece holders for use in connection with machine tools or the like. Y

The principal object of my invention has been to provide a clamp by which the work pieces may be quickly inserted in and withdrawn from a tool jig. 'I'his feature is especially valuable in connection with factory work which is to be done on a production basis. a

Another object has been to provide a clamp for such a jig which may be'operatedto its clamping or unclamping position by a very small movement.

Moreover, my device is'of Iewpa'rts and may be easily and quickly adjusted so as to bring the operating handle of the clamp in the most convenient position vfor operation.

Furthermore.' my clamp is of such 'anature that it will securely hold the work piece in. place.

` 'I'he above objects and advantages have been accomplished by the device shown inthe accompanying drawings, o! which:

Fig. 1 is a front elevation of my device, partly in section.

Fig. 2 is a plan view thereof.

Fig. 3 is an enlarged, perspective view of the clamping member of the device.

Fig. 4 is an end view thereof.

Fig. 5 is a sectional view taken on line B-l or Fig. l.

l While my invention is 'applicable to jigs of various sorts, and while it may be used upon any machine tool which is to be used in operating upon a work piece, I have, for convenience of illustration, shown my device as applied to the bed of a milling machine and'designed to hold a shaft or other round work piece, it being obviousthat slight changes would be made in the 4structure oi? the jig in adapting it to various In the drawings, I represents the bed of the mining machine which is provided with the usuall `Tsbaped slots Il. lAs hereinbefore indicated, the device illustrated is designed for milling or f otherwise working upon ashaft I2 which, as is well understood, is best held in place by means ol a V-block I3, which is rested upon the top sur- Y face I4 of the milling machine and secured in place, if desired, by any well known means.

My device is provided with a. jig member which is preferably angular in shape, having a horizontal arm 2l and a vertical arm 22. The horizontal arm 2l 'isl provided with an aperture 23 for passage over a clamping bolt 24. The

vertical arm 2 2 is provide-du preferably with a' I notch 25'whichi'orms a Vshoulder 26. The distance from the shoulder 26 to the under side of Vthe horizontal arm 2| of the jig member is preierably the same as the distance from the top of 5 the work piece to the, top surface I4 of the table.

The downwardly extending lug 21 thus formed on' the -vertical arm 22 of the -jig member acts as a stop or detent for the jig member.

The clamping bolt 2'4 is carried byone of the 10 .T-shaped slots Il of the milling machine and is provided with a attened lower end 30 for passage between the narrow part of the -T-shaped slot,as clearly shown in Fig. 5. The lower end of the bolt is screwthreaded, and a nut 3| is car- `15 ried at the extreme lower end of the portion 30 and serves to engage-the under surfaces of the r wider part of the T-shaped slot.' A nut 32 and washer 33 are also placed uponv the lower end of the bolt, and these serve to rx'nly secure the bolt 20 within the T-shaped slot, allowing its body part 34 to extend upwardly through the aperture 23 of the jig member. A helical spring 35 is mountv ed upon the bolt under the jig member, whereby the horizontal arm 2l of such member will be moved upwardly when released, thus making-it` convenient to withdraw'the inished work piec from the jig and to insert a new one.

is a `rotatably mounted, anti-friction ball 43. Disposed on the extreme upper lend o1' the body 35 34 of the clamping bolt 24 is the clamping meme ber 44 of my device. This clamping member is screwthreaded to the upper end of the clamping bolt 24 and comprises a clamping head 45 and an operatingv arm 46 extending therefrom in `1Q a horizontal plane. The clamping member is provided o n its under surface with a helically shaped cam 4 1, as clearly shown in Figs. 1, 3,'and 4. This cam, as shown in the drawings, comprises a vhelixof suitable 45 pitch extending through substantially 360. 0bviously, however, two oppositely arranged cams, each extending only through 1330", may be used if desired. The screws and 4I are so adjusted 50 that the anti-friction balls 43 carried thereby,

-will engage with the cam face 41 of the clampingmember. Since the adjusting screws 40 and 4I are arranged diametrically opposite each other, the cam 61 oi the clamping member wil. c6

produce` a uniformly distributed pressure upon the horizontal arm 2| of the jig member.

When my device is to be set up for work upon shafts like those indicated at 2 in Figs. 1 and 2, the horizontal arm 2| of the jig member is brought to bear upon the Work-piece, and the handle 46 of the clamping member is moved to the position where it may be most conveniently operated by the workman. The adjusting screws 40 and 4| are now so rotated that the anti-friction balls 43 carried thereby are brought into engagementwith the cam-shaped surface 41 of the head of the clamping member with substantially equal pressure. When so adjusted, the

set screws 42 are drawn up so as to hold theA screws .40 and 4| in their adjusted positions. Obviously, when the adjusting screws are once set, they do not have to be altered for successive Work pieces since, inthe case of the shaft shown for illustrative purposes, the dimensions are always uniform. After once having been set, the work piece may be securely clamped in position by rotating the operating arm 46 of the 'clamping member in such direction as to cause the cam 41 to push the adjusting screws and the horizontal arm 2| of the jig downwardly in contact with the work piece I2. When the handle is operated in the opposite direction, the work piece will be released andthe spring 35 will cause the jig member 20 and screws 40 and 4| to move upwardly, remaining in contact with the cam 41 of the clamping member, whereby the work piece may be conveniently removed and a new work piece inserted. Such positions are shown by the dotted lines in Figs. 1 and 2.

Obviously, instead of fastening the clamping head 45 onto the bolt by means of screw threads, this head may be rotatably held in placeA on the bolt by means of a collar (not shown).

Obviously, this and other modifications of the details herein shown and described may be made without departing from the spirit of my invention or the scope of the appended claims, and I do not, therefore, wish to be vlimited to the exact embodiment herein shown and described, the form shown being merely a preferred embodiment thereof.l

Having thus described my invention, what I claim is:

1. An adjustable clamp for jigs adapted to cooperate with the bed of a machine tool, comprising a bolt, means for rigidly securing the bolt to the bed, a jig member slidablyl carried by the bolt and having cooperative relation with the bed and a work-piece, a clamping member having an operating handle rotatably carried upon the bolt and in interspaced relation with the jig member, said clamping member being provided with a helically formed working face on its lower surface, diametrically arranged adjusting screws carried by the jig member and having cooperative engagement with the helical face of the clamping member, and means for setting such screws in their adjusted positions.

2. An' adjustable clamp for jigs adapted to cooperate with the bed of a machine tool, comprising a bolt, means for rigidly securing the bolt to the bed, a jig member slidably carried by the bolt and having cooperative relation with the bed and a work-piece, a clamping member having an operating handle rotatably carried upon the bolt and in interspaced relation with the jig member, said clamping member being provided with a helically formed ,working face on its lower surface, diametrically arranged adjusting screws carried by the jig member and having cooperative engagement with the helical face of the clamping member, means for setting such screws in their adjusted positions, and antifriction means carried by the adjusting screws l and engageable with the Workingface of the clamping member.

. FRANK E. STAHL. 

